Bump over broken tooth

I have no dental insurance and no money to see a dentist but I have a tooth that is broken and has been broke for a while and now there is a red bump over my tooth. At first I thought it was just an abcess (abscess) because it was a little swollen. I was given some amoxicillin and IB 800 at the emergency room when I went for pain and after I took that it was fine for a while. Like a week ago I noticed the same feeling over the tooth and slight pain and it went away with pain killers but now there is a red bump and it's not huge but its not what one would call tiny either. The gum area around it is red the bump itself doesn't hurt it just feels weird in my mouth, however the tooth that it is above hurts sometimes. Does this sound like a serious issue, I know I need to go to a dentist or a periodontist but no money. Why do bumps form over the gums? Please help, it's uncomfortable and I'm worried. Thanks so much.